Brachyspira pilosicoli bloodstream infections: case report and review of the literature

Coexistence of Intestinal Spirochetosis and Colorectal Cancer: Could the Coil be Carcinogenic?

Intestinal spirochetosis (IS) is an infectious gastrointestinal disease caused by Brachyspira bacteria. We detail an exceedingly rare case of IS with concomitant invasive colorectal adenocarcinoma (CRC) in a 58-year-old man presenting with abdominal discomfort and fever. Colonoscopic evaluation revealed abnormal-appearing, nodular cecal mucosa and a 35 mm rectosigmoid mass. Histopathology confirmed IS infection and CRC. Our case report is the first to detail IS diagnosed concurrently with colorectal cancer. It highlights the necessity of a high index of suspicion for IS in patients presenting with abdominal discomfort and endoscopic evidence of irregular nodular mucosa, particularly in the setting of suspected CRC. It further details potential pathophysiologic links between IS and colorectal malignancy.

Human intestinal spirochetosis: an entity associated with sexual transmitted infections

INTRODUCTION

Human intestinal spirochetosis (HIE) is a poorly studied clinical entity with variable clinical manifestations. However, in recent years it has gained special relevance because an increasing number of cases have been described in people living with HIV (PWH) and in patients with a history of sexually transmitted infections (STI) or immunosuppression.

METHODS

Retrospective review of all HIE cases identified in a tertiary level hospital (Hospital Universitario la Paz, Madrid) between 2014 and 2021.

RESULTS

36 Cases of HIE were identified. Most cases corresponded to males (94%) with a median age of 45 years. 10 patients (29.4%) were PWH and 20 (56%) were men who had sex with men. Although the clinical manifestations were very heterogeneous, the most frequent was chronic diarrhea (47%), and up to 25% of the subjects had clinical proctitis. 39% percent of patients had been diagnosed with an STI in the previous two years, this characteristic being more frequent in PWH (90% vs. 28%; p < 0.01) than in patients without HIV infection. The STI most frequently associated with a diagnosis of HIE was syphilis (31%).

CONCLUSION

HIE is frequently diagnosed with other STIs and affects mostly men who have sex with men, which supports that this entity could be considered as a new STI.

Ulcerative Proctitis: An Unusual Case of Intestinal Spirochetosis

Human intestinal spirochetosis (HIS) is an uncommon disease characterized by the colonization of spirochetes in the colorectal mucosa and is most often found in individuals who are positive for human immunodeficiency virus (HIV) and in homosexual men. Although HIV is known to cause a variety of infectious colitis, the prevalence has significantly declined with antiretroviral therapy. Intestinal spirochetosis, however, remains meaningful as it can be an infectious cause of colonic ulcerations even with well-controlled HIV. Spirochetosis rarely causes macroscopic changes in the colorectal mucosa and reports of an ulcerated rectum are exceedingly scarce. Here, we report a case of a homosexual man with HIV who is compliant with antiretroviral therapy with high CD4 counts who presented with a six-week history of bloody diarrhea and was found to have multiple ulcerations in the rectosigmoid junction and rectum infected with non-treponemal spirochetes as confirmed on biopsy. To our knowledge, there have not been any reports of multiple rectal ulcerations caused by non-treponemal spirochetes. The patient was treated with metronidazole 500 mg four times daily for 10 days with complete resolution of symptoms. This case is notable as it alerts clinicians to consider intestinal spirochetosis as a differential diagnosis in the workup for bloody stool in the presence of colorectal ulcerations.

Human intestinal spirochetosis, a sexually transmissible infection? Review of six cases from two sexually transmitted infection centres in Barcelona

Human intestinal spirochetosis (HIS) is a possible cause of chronic diarrhoea and affects mainly men who have sex with men (MSM) and people living with HIV. Diagnosis is based on colon biopsy, where spirochetes can be observed on the luminal surface, especially with the Warthin-Starry stain or similar silver stains. We conducted a retrospective descriptive study of all HIS cases diagnosed in two sexually transmitted infections (STI) centres in Barcelona from 2009 until 2018. The medical histories were reviewed to gather epidemiological, clinical, and diagnostic variables. Six patients were diagnosed with HIS. All the individuals were MSM, with a median age of 31.5 years (interquartile range [IQR] 29.5;49.25) and half of them were living with HIV. Five patients reported condomless anal intercourse and 4 patients had practised oro-anal sex previously. Concomitantly, two of them had rectal gonorrhoea, one had rectal Chlamydia trachomatis and none of them had syphilis. The predominant clinical symptom was diarrhoea (5 patients). All cases were diagnosed by a Warthin-Starry stain on a colon biopsy specimen, and mild inflammatory changes were found in 5 cases. Five patients were treated with metronidazole and one with benzathine penicillin G. Treatment was successful in all the patients. HIS should be considered in patients with chronic diarrhoea who report risky sexual practices and/or concomitant STI. HIS may also be sexually transmitted according to the context.

Histologic characteristics of human intestinal spirochetosis in operatively resected specimens

Human intestinal spirochetosis (HIS), one of the zoonoses, is caused by colonization by Brachyspira species bacteria within the large intestine. Histologic diagnosis of HIS is usually established by finding "fringes" on the colonic surface epithelium in biopsy specimens. However, its histologic characteristics, especially beneath the colonic mucosa, have not been elucidated. The present study was designed to examine the histologic characteristics of HIS in operatively resected specimens. We reviewed operatively resected (colectomy or appendectomy) specimens obtained in six consecutive years at a single medical center. HIS was diagnosed histologically by finding "fringes". Immunohistochemical study using anti-Treponema pallidum antibody, which cross-reacts with Brachyspira, was additionally performed. A total of 848 (M:F = 477:371; median age, 59 years; 12-94 years) colectomy and/or appendectomy cases were examined, and the seven cases (0.8%) diagnosed as having HIS were all male (1.5% of male cases). Four HIS cases (0.8% of 508 colectomy cases (1.4% of 285 male-cases)) were colectomy cases with cancers, and the other three (0.9% of 340 appendectomy cases (1.6% of 192 male-cases)) were appendectomy cases for acute appendicitis. Our study revealed (1) a heterogeneous distribution of diagnostically important "fringes" within the large intestine, (2) an ileal presence of Brachyspira, (3) superficial location of HIS-related findings among anatomical wall layers, and (4) the presence of Brachyspira or its derivatives within macrophages in the lamina propria and immune apparatus (lymphoid follicles in superficial wall structures (lamina propria or submucosa) and lymph nodes). Investigation using operatively resected specimens might help elucidate the characteristics of HIS. Brachyspira may have immunogenicity in humans.

Severe Colitis with Portal Venous Gas Caused by Brachyspira pilosicoli Infection

We herein report a case of Brachyspira pilosicoli-caused severe colitis presenting with portal venous gas. A 75-year-old man was admitted because of a fever, severe abdominal pain and bloody diarrhea. He was negative for anti-HIV antibodies. He had been in close contact with a dog earlier. Abdominal computed tomography detected severe wall-thickening and fat-stranding of the entire colon accompanied by portal venous gas. A smear examination of his stool showed many Gram-negative spiral rods, suggesting intestinal spirochetosis. A polymerase chain reaction assay using stool samples detected an amplified band specific for B. pilosicoli. He responded well to antimicrobial agents including metronidazole.

Treponema pallidum Immunohistochemistry is positive in human intestinal Spirochetosis

BACKGROUND

Human intestinal spirochetosis (IS) has been recognized for decades, but whether it represents commensalism or a pathogenic process remains controversial. IS is diagnosed on routine stains with confirmation by silver stains but these stains are labor intensive and slow to read. We evaluated the Treponema pallidum immunostain as a diagnostic adjunct for IS.

METHODS

We retrieved biopsies from 33 patients with IS for this study. Each case was tested by Warthin-Starry (WS) and T. pallidum immunohistochemistry (IHC). Species specific genotyping was performed in 3 cases.

RESULTS

Patients with IS ranged from 22 to 82 years without gender predilection. IS involved normal (n = 15), and inflamed (n = 5) mucosa and colonic polyps (n = 13). Warthin-Starry and T. pallidum IHC were positive in all cases including both species of Brachyspira. Six (18%) symptomatic patients were treated for IS, and experienced resolution. In patients diagnosed with incidental IS on cancer screening (n = 5), follow up biopsies, without therapy, were negative for IS. T. pallidum IHC required 75 min less hands-on time than WS for performance and was faster to interpret.

CONCLUSIONS

T. pallidum IHC can be used to confirm the diagnosis of IS and is easier to perform and faster to interpret than WS.

The Spirochete Brachyspira pilosicoli, Enteric Pathogen of Animals and Humans

Brachyspira pilosicoli is a slow-growing anaerobic spirochete that colonizes the large intestine. Colonization occurs commonly in pigs and adult chickens, causing colitis/typhlitis, diarrhea, poor growth rates, and reduced production. Colonization of humans also is common in some populations (individuals living in village and peri-urban settings in developing countries, recent immigrants from developing countries, homosexual males, and HIV-positive patients), but the spirochete rarely is investigated as a potential human enteric pathogen. In part this is due to its slow growth and specialized growth requirements, meaning that it is not detectable in human fecal samples using routine diagnostic methods. Nevertheless, it has been identified histologically attached to the colon and rectum in patients with conditions such as chronic diarrhea, rectal bleeding, and/or nonspecific abdominal discomfort, and one survey of Australian Aboriginal children showed that colonization was significantly associated with failure to thrive. B. pilosicoli has been detected in the bloodstream of elderly patients or individuals with chronic conditions such as alcoholism and malignancies. This review describes the spirochete and associated diseases. It aims to encourage clinicians and clinical microbiologists to consider B. pilosicoli in their differential diagnoses and to develop and use appropriate diagnostic protocols to identify the spirochete in clinical specimens.

Immunohistochemical detection of human intestinal spirochetosis

Human intestinal spirochetosis (HIS) is a colorectal infection by Brachyspira species of spiral bacteria. Immunohistochemical cross-reaction to an antibody for Treponema pallidum aids its histologic diagnosis. This study's aim was to analyze the immunohistochemical characteristics of HIS. In this analysis, on 223 specimens from 83 HIS cases, we focused on so-called fringe formation (a histologic hallmark of HIS), spiral organisms within mucus or within crypts, and strong immunopositive materials in the mucosa, together with their location and the types of lesions. Fringe formation was found in 81.6% of all specimens and spiral organisms within mucus or within crypts in 97.3% and 57.0%, respectively. Strong immunopositive materials were observed in the surface epithelial layer in 87.9%, in the subepithelial layer in 94.6%, and in deeper mucosa in 2.2% of all specimens. The positive rates in conventional adenomas (24.0%, n = 146) and hyperplastic nodules (100%, n = 17) were each different from that found in inflammation (70.8%, n = 24), and spiral organisms were seen more frequently in the right-side large intestine than in the left (within mucus, 100%, n = 104 versus 95.0%, n = 119; within crypts, 65.4%, n = 104 versus 49.6%, n = 119). Thus, immunohistochemistry was effective not only in supporting the diagnosis of HIS but also in highlighting spiral organisms within mucus or crypts that were invisible in routine histology. Possibly, these spiral organisms may spread throughout the entire large intestine, although there is a potential problem with antibody specificity.

Strains of the intestinal spirochaete Brachyspira pilosicoli attach to and aggregate erythrocytes

The anaerobic intestinal spirochaete Brachyspira pilosicoli colonizes the large intestine of various species of mammals and birds, where it may induce colitis. Strains of the spirochaete have also been isolated from the bloodstream of immunocompromised human patients and have been seen in liver sections, and a similar systemic spread was recently observed in experimentally infected chickens. Some other spirochaete species that may be present in blood attach to and aggregate erythrocytes, and this is believed to contribute to disease severity. The aim of the current study was to determine whether B. pilosicoli strains have the capacity to attach to and aggregate erythrocytes. Initially, four strains of B. pilosicoli were incubated with erythrocytes from sheep, cows, pigs, dogs, humans, chickens and geese, and were observed by phase-contrast microscopy. Only strain WesB attached, and this was only with erythrocytes from chickens and geese. Subsequently, six other strains of B. pilosicoli were tested just with goose erythrocytes, and five attached to and caused aggregation of the erythrocytes. Scanning and transmission electron microscopy demonstrated that spirochaetes abutted and apparently firmly attached to the erythrocyte membranes. Aggregation of erythrocytes by B. pilosicoli may contribute to disease severity in species that develop a spirochaetaemia.

SIGNIFICANCE AND IMPACT OF THE STUDY

The intestinal spirochaete Brachyspira pilosicoli has been isolated from the bloodstream of immunocompromised human patients, and spread to the liver has been reported in humans and in experimentally infected chickens. In this study, B. pilosicoli was shown to undergo attachment by one cell end to chicken and goose erythrocytes in vitro and to aggregate them. This activity has the potential to contribute to disease severity in avian and possibly other species that develop a spirochaetaemia and systemic spread. Avian erythrocytes may be useful for studying the mechanisms by which B. pilosicoli attaches to cells.

The pathogenic intestinal spirochaete Brachyspira pilosicoli forms a diverse recombinant species demonstrating some local clustering of related strains and potential for zoonotic spread

BACKGROUND

Brachyspira pilosicoli is an anaerobic spirochaete that can colonizes the large intestine of many host species. Infection is particularly problematic in pigs and adult poultry, causing colitis and diarrhea, but it is also known to result in clinical problems in human beings. Despite the economic importance of the spirochaete as an animal pathogen, and its potential as a zoonotic agent, it has not received extensive study.

METHODS

A multilocus sequence typing (MLST) method based on the scheme used for other Brachyspira species was applied to 131 B. pilosicoli isolates originating from different host species and geographical areas. A variety of phylogenetic trees were constructed and analyzed to help understand the data.

RESULTS

The isolates were highly diverse, with 127 sequence types and 123 amino acid types being identified. Large numbers (50-112) of alleles were present at each locus, with all loci being highly polymorphic. The results of Shimodaira-Hasegawa tests identified extensive genetic recombination, although the calculated standardized index of association value (0.1568; P <0.0005) suggested the existence of some clonality. Strains from different host species and geographical origins generally were widely distributed throughout the population, although in nine of the ten cases where small clusters of related isolates occurred these were from the same geographical areas or farms/communities, and from the same species of origin. An exception to the latter was a cluster of Australian isolates originating from pigs, chickens and a human being, suggesting the likelihood of relatively recent transmission of members of this clonal group between species.

CONCLUSIONS

The strongly recombinant population structure of B. pilosicoli contrasts to the more highly clonal population structures of the related species Brachyspira hyodysenteriae and Brachyspira intermedia, both of which are specialized enteric pathogens of pigs and poultry. The genomic plasticity of B. pilosicoli may help to explain why it has been able to adapt to colonize the large intestines of a wider range of hosts compared to other Brachyspira species. The identification of a clonal group of isolates that had been recovered from different host species, including a human being, suggests that zoonotic transmission by B. pilosicoli may occur in nature. Evidence for local transmission between the same host species also was obtained.

Intestinal spirochetosis: an enigmatic disease

INTRODUCTION

Intestinal spirochetosis (IS) is a condition in which colonic and appendiceal epithelial cells are colonized by one of two anaerobic spirochetes, either the Brachyspira aalborgi or Brachyspira pilosicoli. There is much debate in the literature as to whether IS is a pathogen or a commensal inhabitant. A recent case of IS at our institution prompted a retrospective database search and review of the literature.

METHODS

A pathology database search for IS was performed at Carolinas Medical Center from 2003 through 2007. After patient identification, a retrospective review of the endoscopic record and the pathology report was performed. Pathology slides were reviewed for accuracy and special silver stains and/or immunostains were performed if needed. The following data were collected for each patient when available: age, gender, nationality, HIV status, and other co-morbid conditions when noted. We attempted to determine whether patients were treated for spirochetosis and if so, the treatment regimen used as well as the results.

RESULTS

The database search detected 29 patients with biopsies showing IS. Three patients were subsequently removed due to incorrect identification. A total of 26 patients with an average age of 45 years were reviewed. The most common symptoms were abdominal pain, diarrhea, and rectal bleeding. Most patients did not exhibit inflammatory changes despite the presence of spirochetosis. Pathologic examination revealed a relative increase in intra-epithelial lymphocytes in a subset of cases, a non-specific finding. Acute colitis or architectural distortion was not seen in any of the study cases. We were only able to obtain follow-up of two patients after treatment with metronidazole and both responded to therapy.

CONCLUSIONS

To date, our study is the largest case series that includes both endoscopic and pathologic descriptions and confirms the "bland" nature of the condition. In <20 % of our patients inflammation was present microscopically and it did not correlate well with endoscopic appearance. Symptoms reported by our patients were similar to those reported in previous studies, although our lack of endoscopic changes was different from one previous paper. There is no established standard of care for the treatment of IS and our study, reflects the enigmatic nature of IS as a disease process. In the absence of rigorous literature, physicians will need to use a logical and pragmatic approach to the evaluation and treatment of IS.

Development of a real-time PCR for identification of brachyspira species in human colonic biopsies

BACKGROUND

Brachyspira species are fastidious anaerobic microorganisms, that infect the colon of various animals. The genus contains both important pathogens of livestock as well as commensals. Two species are known to infect humans: B. aalborgi and B. pilosicoli. There is some evidence suggesting that the veterinary pathogenic B. pilosicoli is a potential zoonotic agent, however, since diagnosis in humans is based on histopathology of colon biopsies, species identification is not routinely performed in human materials.

METHODS

The study population comprised 57 patients with microscopic evidence of Brachyspira infection and 26 patients with no histopathological evidence of Brachyspira infection. Concomitant faecal samples were available from three infected patients. Based on publically available 16S rDNA gene sequences of all Brachyspira species, species-specific primer sets were designed. DNA was extracted and tested by real-time PCR and 16S rDNA was sequenced.

RESULTS

Sensitivity and specificity for identification of Brachyspira species in colon biopsies was 100% and 87.7% respectively. Sequencing revealed B. pilosicoli in 15.4% of patients, B. aalborgi in 76.9% and a third species, tentatively named "Brachyspira hominis", in 26.2%. Ten patients (12.3%) had a double and two (3.1%) a triple infection. The presence of Brachyspira pilosicoli was significantly associated with inflammatory changes in the colon-biopsy (p=0.028).

CONCLUSIONS

This newly designed PCR allows for sub-differentiation of Brachyspira species in patient material and thus allows large-scaled surveillance studies to elucidate the pathogenicity of human Brachyspira infections. One-third of affected patients appeared to be infected with a novel species.

Oral treatment of chickens with Lactobacillus reuteri LM1 reduces Brachyspira pilosicoli-induced pathology

Avian intestinal spirochaetosis (AIS) results from the colonization of the caeca and colon of poultry by pathogenic Brachyspira, notably Brachyspira pilosicoli. Following the ban on the use of antibiotic growth promoters in the European Union in 2006, the number of cases of AIS has increased, which, alongside emerging antimicrobial resistance in Brachyspira, has driven renewed interest in alternative intervention strategies. Lactobacillus-based probiotics have been shown to protect against infection with common enteric pathogens in livestock. Our previous studies have shown that Lactobacillus reuteri LM1 antagonizes aspects of the pathobiology of Brachyspira in vitro. Here, we showed that L. reuteri LM1 mitigates the clinical symptoms of AIS in chickens experimentally challenged with B. pilosicoli. Two groups of 15 commercial laying hens were challenged experimentally by oral gavage with B. pilosicoli B2904 at 18 weeks of age; one group received unsupplemented drinking water and the other received L. reuteri LM1 in drinking water from 1 week prior to challenge with Brachyspira and thereafter for the duration of the study. This treatment regime was protective. Specifically, B. pilosicoli was detected by culture in fewer birds, bird weights were higher, faecal moisture contents were significantly lower (P<0.05) and egg production as assessed by egg weight and faecal staining score was improved (P<0.05). Also, at post-mortem examination, significantly fewer B. pilosicoli were recovered from treated birds (P<0.05), with only mild-moderate histopathological changes observed. These data suggest that L. reuteri LM1 may be a useful tool in the control of AIS.

Intestinal spirochetosis mimicking inflammatory bowel disease in children

Background

Intestinal spirochetosis is an unusual infection in children and its clinical significance in humans is uncertain. The presence of these microorganisms in humans is well-known since the late 1800’s and was first described in 1967 by Harland and Lee by electron microscopy.

Case presentation

This article reports the findings of one pediatric case, review of the current literature, and an overview of therapeutic options.

Conclusion

A high degree of suspicion is required in cases presenting with abdominal pain, chronic diarrhoea and/or hematochezia associated with a normal endoscopic examination, thus emphasizing the importance of multiple biopsies throughout the colon.

Intestinal spirochetosis presenting as acute appendicitis

Acute appendicitis is a frequent pathology encountered by general surgeons. On the differential of aetiologies that can lead to this diagnosis lies the spectrum of infectious disease. We present a case report of a patient who presented to our institution as a classic acute appendicitis. Upon histological analysis it became evident that he had spirochetosis of the cecum and appendix. This paper reviews the literature on this rare infectious aetiology. A synopsis of the microbiology, epidemiology, clinical manifestations and treatments for intestinal spirochetosis is described. At large, the aim of this paper is to heighten awareness of this disease amongst clinicians and specifically surgeons.

Bloodstream infection due to Brachyspira pilosicoli in a patient with multiorgan failure

Brachyspira pilosicoli is an etiological agent of human intestinal spirochetosis. Bloodstream infection due to this microorganism is rare. We report a case of B. pilosicoli bacteremia in a 70-year-old patient who presented with multiorgan failure.

Human intestinal spirochetosis--a review

Human intestinal spirochetosis (IS) is a condition defined histologically by the presence of spirochetal microorganisms attached to the apical cell membrane of the colorectal epithelium. Intestinal spirochetes comprise a heterogeneous group of bacteria. In humans, Brachyspira aalborgi and Brachyspira pilosicoli predominate. Prevalence rates of IS are low where living standards are high, in contrast to poorly developed areas where IS is common. Homosexuals and HIV-infected individuals are at high risk of being colonized. Clinical significance in individual cases has remained unclear up to now. A review of the literature assumes that invasion of spirochetes beyond the surface epithelium may be associated with gastrointestinal symptoms which respond to antibiotic treatment (metronidazole), whereas individuals lacking this feature may be mostly asymptomatic. Of unknown reason, homosexual and HIV-positive men as well as children are more likely to be symptomatic irrespective of invasion. Rare cases of spirochetemia and multiple organ failure have been reported in critically ill patients with IS.

Evaluation of recombinant Brachyspira pilosicoli oligopeptide-binding proteins as vaccine candidates in a mouse model of intestinal spirochaetosis

The anaerobic intestinal spirochaete Brachyspira pilosicoli colonizes the large intestine of humans, and various species of animals and birds, in which it may induce a mild colitis and diarrhoea. The aim of the current study was to evaluate the use of putative oligopeptide-binding proteins of B. pilosicoli as vaccine components. A partial genome sequence of B. pilosicoli porcine strain 95/1000 was subjected to bioinformatics analysis, and six genes predicted to encode oligopeptide-binding proteins were selected. Following a PCR-based distribution study of the genes across different strains of the spirochaete, they were amplified from B. pilosicoli human strain WesB and cloned in Escherichia coli. The recombinant histidine-tagged proteins were purified and subjected to in vitro and in vivo immunogenicity analysis. Recombinant products (P-1 and P-3) from two genes that were immunogenic and recognized by sera from pigs that had recovered from B. pilosicoli infections were tested in a mouse model of intestinal spirochaetosis. For each recombinant protein, groups of 12 C3H/HeJ mice were vaccinated subcutaneously with 100 microg protein emulsified in Freund's incomplete adjuvant, twice with a 2 week interval. Two weeks later the vaccinated and non-vaccinated control animals were challenged orally with B. pilosicoli strain WesB. Both proteins induced systemic and local colonic IgG antibody responses, and, following experimental infection, the cumulative number of colonization days was significantly (P<0.001) less in both groups of vaccinated mice compared to the control mice. There were significantly (P=0.012) fewer mice colonized in the group vaccinated with P-1 than in the non-vaccinated control group. The results suggest that oligopeptide-binding proteins may have potential for use as components of vaccines for B. pilosicoli.